Chemistry Commons^™

Fundamental Studies Of Bimetallic Model Surfaces And Metal Organic Framework Thin Films, Fathima Sharfa Farzandh

Theses and Dissertations

This work is mainly focused on gaining a fundamental understanding of conventional bimetallic catalysts in order to correlate their macroscopic properties with the observed kinetic properties. This is achieved by synthesizing and studying fundamental model surface analogues of conventional catalysts that are difficult to study due to their complex, ill-defined nature. A wide array of surface science techniques that use ultra-high vacuum (UHV) conditions are readily available for detailed studies that can be conducted on model surfaces. This work focuses on the synthesis and investigation of two fundamental bimetallic catalysts formed via the addition of a second metal to an …

In Situ Monitoring Of Catalytic Molecular Transformations On Noble Metal Nanocatalysts Using Surface-Enhanced Raman Spectroscopy, Hui Wang, Qingfeng Zhang, Esteban Villarreal, Hao Jing, Kexun Chen

Journal of the South Carolina Academy of Science

Noble metal nanoparticles have long been of tremendous interest in the nanophotonics and nanocatalysis communities owing to their intriguing size- and shape-dependent plasmonic and catalytic properties. The combination of tunable plasmon resonances with superior catalytic activities on the same noble metal nanoparticle, however, has long been challenging because the research on nanoplasmonics and nanocatalysis deals with nanoparticles in two drastically different size regimes. While tunable plasmon resonances are a unique feature of metallic nanoparticles in the sub-wavelength size regime, heterogeneous catalysis requires the use of substrate-supported sub-5 nm nanoparticulate catalysts. In this mini-review article, we share with the readers several …

Synthesis And Design Of Novel Polymer Grafted Nanoparticles Relevant To Drug Delivery Vehicles For Biomedical Application, Maan Abduldiyem Hassan Al-Ali

Theses and Dissertations

The modification of inorganic nanoparticles with organic polymer chains has become a significant field of study for the engineering of advanced nanocomposite materials. This dissertation presents the design, synthesis, and characterization of novel polymer grafted silica nanoparticles as new strategies to combat bacterial resistance. Described herein is the synthesis of monomers that have been graft polymerized onto silica nanoparticles that can be used as a delivery drug vehicle for biomedical applications. The polymerization of these monomers was performed via reversible addition-fragmentation chain transfer (RAFT) polymerization. The molecular design of the RAFT agents that are attached to the surfaces of the …

Macromolecular Engineering Of Biomass Polymers And Stimuli-Responsive Materials Towards Enhanced Thermomechanical Properties, Meghan E. Lamm

Theses and Dissertations

Commodity polymers are used in every aspect of daily life, and most of these polymeric materials are synthesized using petroleum-derived sources. There are direct environmental consequences to this petroleum dependence including greenhouse gas emissions and climate change. Biomass-based polymers show promise for the mitigation on negative environmental impact, in comparison with petroleum-derived counterparts. However, some biopolymers suffer from low chain entanglement due to bulky or long side chain structures, resulting in poor mechanical properties. In this dissertation work, macromolecular engineering is used to design biomass-derived polymers featuring a variety of structures and functionalities. Additionally, biopolymer properties (including thermomechanical enhancement) and …

Cdse Quantum Dot Surface Chemistry Thermodynamics Via Isothermal Titration Calorimetry: An Emphasis On The Fundamentals, Megan Y. Gee

Theses and Dissertations

For several decades, the study and development of colloidal semiconductor nanocrystals, or quantum dots (QD), has become a rich field heralding improved integration into applications ranging from photovoltaics and photocatalysis to biomedical imaging and drug delivery. CdxSey is the most extensively studied QD system, however numerous compositional details still confound the nanocrystal field. Although CdSe QDs with native ligand coatings can show high fluorescence quantum yield and may be suitable for some applications, often times these original ligand layers are comprised of long aliphatic chains that preclude incorporation into biological matrices or severely impede charge transfer – depending on the …

Ultra-Fast Sensors To Study The Fundamental Neurochemistry Underlying Disease, Alyssa West

Theses and Dissertations

Serotonin is a vital neurotransmitter whose exact roles are ill-defined. Dysfunctions in serotonin signaling are thought to underlie a myriad of neurological problems including depression and autism spectrum disorder (ASD). Prior to investigating serotonin’s role in disease states, one must understand more about the functionality of serotonin in healthy in vivo models. To study serotonin in vivo, fast-scan cyclic voltammetry (FSCV) and fast- scan controlled adsorption voltammetry (FSCAV) are employed to measure evoked and basal serotonin concentration, respectively. These methods, combined with mathematical modeling, provide information regarding regulatory mechanisms of serotonin neurotransmission. FSCV and FSCAV are first applied to …

Self-Assembly And Emergent Properties Of Urea Tethered Triphenylamines For The Formation Of Regenerable Radicals, Ammon J. Sindt

Theses and Dissertations

Self-assembly of photoactive compounds in the solid-state can give rise to new photophysical properties. Key to these properties, is how these compounds can be organized in a uniform way. For this, hydrogen bonding building blocks can be used to guide the assembly of these compounds into organized structures. For instance, ureas, thioureas, and squaramides which contain both hydrogen bond donors and acceptors can guide the assembly of small m-xylene macrocycles in three distinct manners: 1-D columns, edge-to-face Herringbone patterns, and interdigitated networks. The former of these is commonly employed in our group to make either linear or macrocyclic dimers …

Heterogeneous Ozonation Of Model Drinking Water Contaminants Using Cbv-720 Zeolite, Benson Maxwell Solomon

Theses and Dissertations

Advanced Oxidation Processes (AOPs) are designed to remove aqueous organic contaminants through their reaction with hydroxyl radicals (HO∙). Ozone is classified as an AOP due to its ability to produce hydroxyl radicals, as well as its ability to oxidize a wide range of organic contaminants. Due to the unselective nature of hydroxyl radicals, many organic and inorganic co-solutes can act as scavengers, reducing the efficiency of an AOP. Here we show a probe system for testing the hypothesis that adsorptive ozonation of contaminants may yield a more selective environment that favors neutral contaminant oxidation over oxidation of co-solutes.

Initial experiments …

Synthesis And Characterization Of Hyaluronic Acid Based Biomaterials For Drug Delivery And Virus Modification, Amanda Wagner

Theses and Dissertations

In this thesis, hyaluronic acid based biomaterials are studied. The properties and potential applications of these polymers are characterized and discussed.

In Chapter 1, biomaterials are introduced as well as hydrogels and nanogels. Hyaluronic acid is highlighted as a remarkable bio-polymer. The overall objectives of my research are also discussed.

Chapter 2 is focused around trials for utilizing graphene oxide as a nanomaterial for controlling the drug release of an aromatic compound. Hyaluronic acid based hydrogels were synthesized as a delivery vessel. The results of the drug release profiles are examined and discussed.

A different direction is taken in Chapter …

Studies Of Ch Activation In Unsaturated Amides And Esters By Trinuclear Metal Carbonyl Clusters Of Osmium, Morteza Maleki

Theses and Dissertations

The chemistry of the reaction of Os3(CO)10(NCCH3)2 with representatives of unsaturated amides and esters, RCOCHCH2 (R=(CH3)2N, CH3O) has been investigated. In these reactions, it has been observed that a CH bond on the β-carbon atom is readily activated by triosmium carbonyl clusters. The activation of β-carbon C-H bond in unsaturated amides and esters provides a robust platform for studying multicenter C-H bond transformations and for C-C bond formation via hydrogen shift and CO insertion processes. In this work, proposed mechanistic approaches have been taken in order to better understand and study the relationship between the characterized species. In addition, a …

Frontiers In Fast Voltammetry: Novel Analytes And Applications, Jordan Holmes

Theses and Dissertations

Electrochemical sensors are beneficial towards the development and advancement of monitoring devices. As this type of technology progresses, so does our ability to create state-of-the-art sensing strategies to probe environmental and biological systems at the source. In the environment, it is essential to monitor particularly harmful contaminants like trace metals in order to better mitigate risk. Additionally, biological molecules are often times challenging to measure because matrices are complex and difficult to probe; Recent advancements in chemical ex vivo and in vivo sensing platforms have offered insight into physiological processes. The brain in particular requires a sophisticated, implantable sensor as …

Designing, Constructing, And Employing Two-Dimensional Ultrafast Spectroscopy To Resolve Complex Kinetics, Jason R. Darvin

Theses and Dissertations

Multiple population-period transient spectroscopy (MUPPETS) is a two dimensional ultrafast time resolved spectroscopy technique. MUPPETS uses three pairs of optical pulses over two time periods to separate homogeneous and heterogeneous causes of rate dispersion. This dissertation details improvements to the MUPPETS optical assembly enabling measurements on systems that previously fell outside of the MUPPETS 2-ns time window. In addition, the theoretical groundwork is laid to unveil the hidden coordinate controlling rate exchange using 2D and 3D correlation functions.

The first project details improvements made to the MUPPETS assembly. A detailed method was developed to eliminate astigmatism, coma, and spherical aberration …

Study Of Transition State Stabilization Using Molecular Rotors, Erik Carl Vik

Theses and Dissertations

Molecular devices that function as rotors and measurement devices are the main topic of this dissertation. Each study contains a device based on an N-phenylimide framework, which has restricted rotation about the N-C (imide-phenyl) single bond due to a steric clash from the imide carbonyl and the phenyl rings ortho substituent. In general, two ground states are observed by 1H NMR, which are separated by a single transition state (TS). Incorporation of non-covalent interactions into the TS led to measurable changes in the rate for rotation. While the molecules in this dissertation revealed details that could not have been predicted, …

Studies On The Mechanism And Application Of Steam Thermography, Raymond Gerard Belliveau Iii

Theses and Dissertations

The detection of blood on fabrics for forensic purposes is a widely studied topic in forensic science, and to that end, effort in this laboratory has been devoted to developing a thermal imaging method called steam thermography. Steam thermography is a method used to enhance chemical contrast in thermographic images by exposing a surface to water vapor during imaging. The exposure of water vapor to the surface generates heat, and can differentially increase the thermographically measured apparent temperature of imaged surfaces. This can result in thermographic contrast between surfaces with different chemical properties. Previously reported proposed mechanisms to describe the …

A Spatial Heterodyne Spectrometer For Raman Imaging And Remote Spectroscopy, Ashley Nicole Allen

Theses and Dissertations

Raman and Laser-Induced Breakdown Spectroscopy (LIBS) are optical techniques that provide information about the chemical makeup of a sample without any preparation or physical contact with it. For this reason, Raman and LIBS spectrometers are among the instruments selected for NASA’s Mars 2020 rover mission and are being considered for future missions to the Jovian moons, asteroids and comets. Such future missions will require smaller, more ruggedized Raman and LIBS spectrometers, and the new type of spectrometers discussed here, the spatial heterodyne Raman and LIBS spectrometers are being developed for this purpose. The SHS is a wide-field, Fourier transform, stationary …

Cationic Cobaltocene Derivatives And Polyelectrolyte Membranes For Energy Storage Applications, Tianyu Zhu

Theses and Dissertations

Metal-containing polyelectrolytes (or metallo-polyelectrolytes) represent a new class of polymeric materials with distinct properties compared to traditional organo- polyelectrolytes or neutral metallopolymers. This emerging class of synthetic materials is ubiquitous for a myriad of utilities ranging from traditional electrolyte chemistry to biomedicals to sustainable applications, to name just a few. This dissertation work is focused on the design, synthesis, characterization and application of advanced metallo- cations and metallo-polyelectrolytes for energy storage applications. First, a template method to prepare metallo-polyelectrolytes based on cationic cobaltocene and polyethylene backbone was described. The resulting membranes are mechanically tough, ionically conductive and chemically inert. Second, …

Elucidating The Mechanism Of Bone Morphogenetic Protein (Bmp) -Mediated Sox2 Downregulation In Ovarian Cancer, Zainab Motolani Shonibare

Theses and Dissertations

Sex determining region Y-box 2 (Sox2) is a transcription factor essential for maintaining self-renewal and pluripotency of undifferentiated embryonic stem cells. Sox2 is involved in multiple processes of cancer cells, however, regulation of Sox2 expression and the consequences of that regulation in cancer remains elusive. Previously, we demonstrated that BMP9/GDF2 is significantly reduced in expression in ovarian cancer (OVCA) cells, methylated in patient tumors and, promoted anoikis resistance in both breast and OVCA cell lines. In an attempt to identify genes downstream of BMP9 that may provide anoikis resistance, transcriptomics was performed leading to the identification of Sox2, a developmental …

Investigation Of Electrostatic Interactions Towards Controlling Silylation-Based Kinetic Resolutions And Exploring The Effect Of The Polymer Backbone On Silylation-Based Kinetic Resolutions Employing A Polymer-Supported Triphenylsilyl Chloride, Tian Zhang

Theses and Dissertations

This dissertation focuses on studies of silylation-based kinetic resolution methodology developed by the Wiskur group, which is a powerful method for the separation of a single enantiomer from a mixture of racemic secondary alcohols. Chapter 1 introduces the background of our silylation-based kinetic resolution..

Chapter 2 involves mechanistic studies of electrostatic interactions in controlling enantioselectivities of our silylation-based kinetic resolution. Electrostatic interactions between a silylated isothiourea intermediate and an ester π system is determined via linear free energy relationship study. To be specific, how variations in sterics and electronics affect the selectivity of a silylation-based kinetic resolution.

Chapter 3 is …

The Development Of Multi-Functional System That Combine Patterned Hydrogels, Plasmin-Degradable Nanoparticles And Stem Cells For Applications In Tissue Engineering And Growth Factors Delivery, Safaa I. Kader

Theses and Dissertations

This thesis spots the light on the development of a novel multi-functionalized system for application in tissue engineering and on-demand morphogens delivery. Three types of materials used in this study are synthetic polymer, biopolymer, and nanomaterials. Polyethylene glycol (PEG), a synthetic polymer was chosen in this study because of its high biocompatibility, non-immunogenicity, inert nature, ease of modification, and reduces protein denaturation to provide a wide range of physical and mechanical properties. Here, PEG is used one time as a hydrogel, linear polyethylene glycol-co-lactide (LPELA), and another time as peptide-PEG based nanoparticles (PxSPCP). Gelatin, a natural polymer has been widely …

Rompi-Cdsa: Ring-Opening Metathesis Polymerization-Induced Crystallization-Driven Self-Assembly Of Metallo-Block Copolymers, Ye Sha, Md Anisur Rahman, Tianyu Zhu, Yujin Cha, C Wayne Mcalister, Chuanbing Tang

Faculty Publications

Polymerization-induced self-assembly (PISA) and crystallization-driven self-assembly (CDSA) are among the most prevailing methods for block copolymer self-assembly. Taking the merits of scalability of PISA and dimension control of CDSA, we report one-pot synchronous PISA and CDSA ring-opening metathesis polymerization (ROMP) to prepare nano-objects based on a crystalline poly(ruthenocene) motif. We denote this self-assembly methodology as ROMPI-CDSA to enable a simple, yet robust approach for the preparation of functional nanomaterials.

Preface To Special Issue “International Year Of The Periodic Table: From Mendeleev To Cluster Chemistry”, Richard D. Adams, Boon Teo, Vladimir P. Fedin

Faculty Publications

No abstract provided.

Table Of Contents

Journal of the South Carolina Academy of Science

No abstract provided.

Synthesis Of Stimuli-Responsive Programmable Polymers Through Ring-Opening–Metathesis Cross-Metathesis (Rom-Cm), Courtney S. Dziewior, Sharon M. S. Strickland, Ping Li, Ken D. Shimizu

Journal of the South Carolina Academy of Science

Stimuli-responsive polymers can change their physical and/or chemical properties in response to external stimuli. These polymers have found great success in a number of important areas including molecular gels and biomedical engineering, as well as success in applications such as targeted drug delivery and biosensors. We have been working toward the development of programmable polymers that remember the response after a stimulus is withdrawn. To this end, we set out to synthesize specific functional monomers. While different types of reactions could potentially result in the desired target monomer, we studied the ring-opening metathesis–cross-metathesis reaction (ROM-CM). Previous work of ours synthesized …

The Effect Of Confinement On Fe2o3 Nanoparticles In Free Diffusion And With A Horizontal Magnetic Field, Patrick Simonson, Ashely Rice, Gabrielle Seymore, Ana Oprisan

Journal of the South Carolina Academy of Science

We investigated the magnitude of the confinement effect's influence on the free diffusion of Iron Oxide Fe₂O₃ in pure water contained in cells of different volumes and also that of an applied magnetic field. A shadowgraph apparatus consisting of a super luminous diode (SLD) source, a CCD camera, and achromatic lenses was used to record and analyze the changing indices of refraction due to the presence of concentration-driven fluctuations as the solution diffuses. Extracted frames from this recording were processed through a Differential Dynamic Algorithm (DDA) that determined the dynamics of the process, such as the structure …

Studying Near-Critical And Super-Critical Fluids In Reduced Gravity, Christian Hawkins, Ana Oprisan, Carole Lecoutre-Chabot, Yves Garrabos, Daniel Beysens

Journal of the South Carolina Academy of Science

Critical and supercritical fluids have a variety of applications, from use as machine lubricants in high pressure or high temperature environments to the manufacturing of materials such as aerogel. The optical properties of fluids undergo rapid changes near the critical point resulting in a rapid increase in turbidity known as critical opalescence. These optical changes can be used to probe the universality of critical behavior. As a fluid approaches the critical point, the compressibility rapidly increases. In a gravitational field, this increase in compressibility leads to near-critical fluids stratifying by phase and density, making it difficult to observe the optical …

Fluidic Control System Development For Fluorescence Imaging Photometer, Ergün Kara

Theses and Dissertations

Phytoplankton are the primary autotrophic organisms in the marine food web and they produce nearly half of the global oxygen as a photosynthetic by-product [1]. Through photosynthesis, phytoplankton annually fix between 30 and 50 billion metric tons of atmospheric carbon into the marine systems, which approximately accounts for 40% of total carbon fixation [2]. Furthermore, the phytoplankton population trends are important indicators of the environmental perturbations [3]. Therefore, detection and characterization of the phytoplankton species is an important goal of the science. Several spectrometric, cytometric and microscopic techniques are already employed for characterization and quantification of the phytoplankton communities [4-6]. …

Disinfection By-Products: Method Optimization For Quantification, Unknown Analysis, And Calculated Toxicity, Amy A. Cuthbertson

Theses and Dissertations

Disinfected drinking water contains hundreds of disinfection by-products (DBPs) that are formed by the reaction of disinfectants with natural and anthropogenic organic matter, bromide, and iodide. Understanding what these DBPs are is important because millions of people worldwide consume drinking water every day, and human epidemiologic studies have reported cancer, miscarriage, and birth defects from consuming such waters. While more than 700 DBPs are reported in the literature, very few studies quantify complete classes of chlorinated, brominated, and iodinated DBPs. The following document contains five chapters in the format designated for specific scientific journals on this subject. Chapter 1 describes …

Non-Destructive Determination Of Magnetic Audio Tape Degradation For Various Tape Chemistries Using Spectroscopy And Chemometrics, Alyssa Marie Abraham

Theses and Dissertations

This dissertation focuses on creating a non-destructive method for the identification of degraded magnetic audio tapes using attenuated total reflectance Fourier transform infrared spectroscopy (ATR FT-IR) and chemometrics. The primary recording medium during the second half of the twentieth century was magnetic tapes. These tapes hold some of the world’s modern cultural history. Unfortunately, the majority of these tapes were made with a polyester urethane (PEU) binder, which has shown to degrade through hydrolysis of the ester component, called sticky shed syndrome (SSS). As the name implies, degraded tapes will stick and shed onto player guides and heads during playback. …

Semiconductor Nanowire Doping: Controlling Magnetic And Electronic Properties Of Colloidal Nanowares, Preecha Kittikhunnatham

Theses and Dissertations

Electronic devices have been utilized in a wide range of applications, such as computing, data storage, sensors, lightings, energy production, and energy storage; they are building blocks of computer processors, solid state data storage devices, image sensors in digital cameras, LEDs, and solar cells, etc. These electronic devices operate based on properties of semiconductors, which are their essential components. Not only being fundamental components of electronic devices, semiconductors can be crucial materials for other applications, such as catalysts, battery electrodes, etc. One of the primary current quest on semiconductor research is to develop semiconducting materials that are more compact and …

Model Pt-Re And Pt-Sn Surfaces For Heterogeneous Catalysis, Thathsara Deshani Maddumapatabandi

Theses and Dissertations

The dissertation is focused on understanding the growth, morphology and activity of model heterogeneous catalytic surfaces. Vapor deposited metal clusters on single crystal surfaces are well-defined systems that can be used to understand the growth, composition and activity relationships in commercial catalysts. A fundamental understanding of surface reactions is required in order to provide insight into the development of new catalytic materials. The model catalysts approach allows for systematic investigations due to excellent control over growth, composition and characterization under a carefully controlled ultrahigh vacuum (UHV) environment.

The nucleation, growth and chemical activity of monometallic and bimetallic Pt-Re clusters on …